Magnetic means for controlling an electric arg



Meirch 26, 1935. .1. o. ARMSTRONG 5, 6 MAGNETIC MEANS FOR CONTROLLING ANELECTRIC ARC I Filed April 14, 1932 '2 Sheets-Sheet 1 a &- a a.

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March 26, 1935. J. o. ARMSTRONG 1,995,560

MAGNETIC MEANS FOR CONTROLLING AN ELECTRIC ARC Filed April 14, 1952 ZSheets-Sheet 2 E 7 W p 0 fwme-5 0. JZrmairoQg;

the core of an inch,the thickness of'thecore (at right angles to theelectrode) 3' of aninch,

the distance between the upper poles of'the'mag-Q the flame maybe causedto assume and retain a netsfrom 4 to 6 inches, the distance between thecenter lines of the magnets El /3111161185, and the height of the upperpoles of the magnet above.

the electrode from 1 to 2 inches. 1

The windings of v the electromagnets may be as follows:

"-1- el'ectrode T electrode Ampere turns 9 m. m. 255m 270 9 or 10 m. m.300 to 330 -ll m. In. 250 to 320 vir'ewing the arrangement fro m th efront of the crater, the left hand electromagnet should have-an upperpole whichfis N and a lower pole S. and the right hand. electromagnetshould be.

just the opposite, namely, the upper, poleshould V be S and the lowerpole should'be N.

" As shown in Figs. 4, and fijtwo electromagnets are provided. These1electromagnets are comprisedof cores oand windings p. Theelectromagnets are mounted upon brackets q which are carried by thefront contact b'oi the.lamp.-

The'brackets q are slottedas at r and s so as to enable the positions ofthe electromagnets .to be adjusted vertically and horizontally. T

If desired, means (not shown) may also be'provided for adjusting theelectromagnets angularly' about axes parallel with that of the positive,fcarf bon a, but such movement is not usually. nec

essary. V V,

The front edges of the cores 0 normally lie in a plane about 1%inchesbehind the crater d, that is to say; substantiallyin a line withthe central plane of the, apertured plate e. ,Generally speaking; aboutinch is suificient to cover any adjustment which may be necessary.

Ifdesired; however, the electromagnets may be capable of adjustment sothat the front edges of the cores 0 maybe between 1 and 2 inches fromthe crater d. 'The upperportions of the cores 0 are bent towardseachotheraround the positive carbon at as at t,' 'while their lower endsu are bent towards" each other at right angles.

- For some unknown reason; the use of the slotted iron plate e producesan increase in the brilliancy of the arc, that is, an increasedwhiteness of the light. This is possible because the magnetic field setup increases the intensity of combustionin the crater and increases thepro? portion of blue in the light produced. The in crease in intensitybecomesgreater as the plate is movedtowards the crater of the positivecarbon. This distance, however, is limited first by reason of the heatof the crater and its effect on the metal, and second, becau se theflame of the arc is attractedtowards the plate e proportion to-itsproximity to the crater. v The flame is drawn towards the gap' hand the'widthof the flame tends to vary with the width of said gap.

The attraction of theflflame by the plate e is decreased as the diameterof the aperture'f is increased, but such increase in diameterreduces theeffect of the plate.

The employment of electromagnets, as set forth above, enables the arcflame to be'blown away from-theplate e, and thus permits the latter tobe moved nearer to the crater, consequently increasing its effect. Bysuitably adjusting the characteristics of the plate 6 and theelectromagnets and their positions relative to each other, and to theposition of the crater, a great increase inthe brilliancy of a light maybeobtained while concentrated form extending vertically above thecrater.

By means of this invention the arc-flame of an electric arc lamp may bestabilized in a vertical position and narrow formation .of particularlypositive electrode, said electromagnets being adjustably mountfedforlimited movements in the direction of their lengths and, also in thedirection of and? angularly 1 about, axes parallel with that of thepositive'electrode. r j

2. Means ior'bontrolling an "electric arc "com prisi'ng'a plate of ironaperturedjfor the passage of the positive carbon and arranged in therear of thearc crater and having a relatively narrow gap above saidcarbon, in combinationwith a pair of electro-magnets arranged'one oneach side of the positive electrode, the cores,ofsaid electro-magnetsLbeingbent at their upper ends so as to be substantially coaxial withthe positive electrode and near theirlower ends at right angles towardsthe median plane of the'lamp. I

3. Means for V controlling an electric arc as claimed in. claim 1,wherein the upper ends of the cores of the electro-Imagnets arebenttowards one another in 'a circular curve, whilst the'lower ends ofsaid cores jare bent' towards one another at right angles. 1

4.. In. an arc lamp, the combination of means for controlling theelectricarc, said means comprising a plate'of ironpro'vided withanaperture and disposedto the rear of the crater oi the arc,

the positive. carbon or the arc lamp passing .through'said aperture,'said plate having a relatively narrow .gap above said carbon, and a pairof. electromagnets arranged substantially vertically one at each side oithe positive electrode and substantially in the same general plane, as,said apertured plate, said. electromagnetsjbeing connected sothatthemagnetic flux between the poles of each thereof flows in thegeneral direction'of that of the 'adjac'entp'art of said aperturedplate.

5. In an electric arc lamp, meansfor controlling the electric arccomprising a plate .or iron

